Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor superfamily. Similar to other members of the tumor necrosis factor superfamily, soluble TRAIL forms a homotrimer, which cross-links three receptor molecules on the surface of target cells, thus inducing the biological functions. The apoptosis inducing function of TRAIL is realized by its interaction with the death receptor 4(DR4) and DR5 on the tumor cells through death signal transmission. Although other members of tumor necrosis factor superfamily are restricted due to their systemic side effects, TRAIL is a relatively safe agent for cancer-specific therapy. TRAIL induces apoptosis in a variety of tumor cells and cancer cells in vitro, and shows substantial anti-tumor activity in rodent xenograft models, including colon cancer, breast cancer, multiple myeloma, glioma, prostate cancer and many other models. Particularly important, when drugs were administered to mice and non-human primates, TRAIL presented little or no toxicity. For the above reasons, recombinant TRAIL has been used in clinical trials for tumor treatment. However, some recent reports showed that, in addition to inducing tumor cell apoptosis, TRAIL is also involved in innate immunity and adaptive immunity, associated with autoimmune diseases. For example, recent studies have reported that TRAIL can regulate the negative selection or apoptosis of thymus cells during the thymus development process, and plays an important role in inducing autoimmune diseases such as type I diabetes. In addition, TRAIL receptors are extensively expressed in the whole body, and TRAIL also plays a role in liver cell death and hepatitis. Therefore, repeated and systemic use of high-dose exogenous TRAIL may lead to unforeseen immunological effects in clinic. As a result, there are serious concerns about the potential side effects of repeated and systemic use of TRAIL. Thus, there exists a need for a compound, method of preparation, and method of application of a TRAIL fusion protein which avoids the above mentioned deleterious side effects of wild-type TRAIL.